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NN_97712471-Visitor
1-Visitor
January 6, 2021
Question

Create minimal surfaces by equation

  • January 6, 2021
  • 1 reply
  • 5324 views

Hello,

 

Please, I need to create differently minimal surfaces. I know how to create gyroid, diamond, and schwarz P throught engineering - lattice - formula driven. (https://support.ptc.com/help/creo/creo_pma/r6.0/usascii/index.html#page/part_modeling/part_modeling/...)

But It is not exactly what I need. Because I am creating structures with differently porosity and I am limited by wall thicknes and it can not be smaller than some value... Also I want to create other structures like Neovius, Schoen IWP... (And in Formula driven are just three structures) So is the way how to create minimal surfaces by equation ? Or is the another solution how to create this structures with small porosity (about 10%) ? I tried curve from equation, but still had errorr...

 

 Please I really need it.

 

Thanks for help, and sorry for my english language.

1 reply

tbraxton
22-Sapphire II
tbraxton22-Sapphire II
22-Sapphire II
January 6, 2021

Creo does not support explicit creation of surfaces from equation, only curves from equation. To create surfaces from equations in Creo you must use curves (from equation) as construction geometry to build surfaces as children of the curves.

 

I think you are looking to employ a custom lattice.

https://support.ptc.com/help/creo/creo_pma/r6.0/usascii/index.html#page/part_modeling%2Fpart_modeling%2Fpart_nine_sub%2FTo_Create_Custom_Lattice.html%23 

 

If you can define a unit cell parametrically in math terms you can create the 3D surfaces in another tool such as Mathematica and then export the unit cell to Creo using a neutral file format. Mathcad may be an option as well to get the unit cell geometry.

N
NN_97712471-VisitorAuthor
1-Visitor
January 9, 2021

Thank you for your answer. I created one cell with gyroid structure by equation... Saved it to STL format. And then I Opened this STL file in Creo and changed to PRT. So Now I have one cell of gyroid structure in prt file. So I tried to use custom lattice structure, but when I added this cell into it I still got  error: Incompatible part size/accuracy. Change PRT0001 accuracy to 0.000000 or use absolute accuracy to match part accuracies.
Failed to create the required lattice template. Something is wrong because when I changed accuracy to absolute, I got next Error: Incompatible part size/accuracy. Change PRT0001 accuracy to 0.000003 or use absolute accuracy to match part accuracies.Do you know what to do with this?

 

Thank you

tbraxton
22-Sapphire II
tbraxton22-Sapphire II
22-Sapphire II
January 9, 2021

In Creo 7 absolute accuracy is the default. If you are not using Creo 7 to create these models then they may use relative accuracy. 

I believe the warning error is suggesting to match the absolute accuracy of your design model and the model of the unit cell.

 

In this specific instance it sounds like the error is due due incompatible accuracy between your unit cell and the model you are applying it to.

 

Change to absolute accuracy in your design model (e.g. if units of length is mm then set accuracy to .001 mm). Create a start part with absolute accuracy matching that of your design model. Import your unit cell into a new part using the abs accuracy template. You can then try again to apply the custom lattice.

 

http://support.ptc.com/help/creo/creo_pma/usascii/index.html#page/part_modeling/part_modeling/part_five_sub/To_Set_Part_Accuracy.html 

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